Flatbed scanners typically perform a preview scan of an image that generates preview image data. The preview image data is then displayed in a viewing region of a user interface. The user interface allows the user to select an image region of the scanned preview image. A final scan is performed on the image region selected by the user.
The preview scan provides a user with great flexibility in selecting the image region; however, the use of a preview scan does require steps to be performed by the user before the final scan is performed. These steps performed before the final scan can be cumbersome and time consuming depending upon the speed of the scanner and the processing software.
Some flatbed scanners include half-rate and full-rate carriage devices. These devices, for example, involve a method used in some flatbed scanners for transporting scanner optics, such systems keep a constant distance between the imaging sensor and the document being scanned. Flatbed scanners also can incorporate the use of a CCD (Charge Coupled Device). A CCD is the most common type of imaging sensor in flatbed scanners, although other devices such as CIS (Contact Image Sensor) or FWA (Full Width Array) devices can be employed. A typical CCD sensor includes, for example, an array of light detectors that measure the differences in the intensity of the reflected light gathered from an original being scanned.
One of the problems with current flatbed scanners, particularly in the context of a MFD (Multi-Function Device), is that document size sensing on MFD scanners typically works by determining the document length in the fast scan direction using the devices imaging sensor and the width using one or more fixed size position sensors to distinguish between different but similar document sizes (e.g., A4 versus US letter) and long or short documents such as A4 and A3, where the fast scan length is the same. In some cases it may be difficult to physically locate the two fixed sensors as they may interlace with the moving optics within the scanner, and even if they can be mounted because they are fixed in position there is a limitation to the different paper sizes that they can resolve.
Based on the foregoing, it is believed that a need exists for an improved scanner apparatus and flatbed scanning system/configuration, as will be described in greater detailed herein.